Point-to-point protocol flow control extension

• US 7,558,872 B1
• Filed: 04/28/2006
• Issued: 07/07/2009
• Est. Priority Date: 01/31/2002
• Status: Expired due to Term

• Current Assignee: Dell Marketing Corporation (Dell Technologies Inc.)
• Original Assignee: Force10 Networks, Inc. (Dell Technologies Inc.)
• Inventors: Sikdar, Somsubhra, Senevirathne, Tissa
• Primary Examiner(s): Lin; Kenny S
• Application Number:
  US11/413,909
• Time in Patent Office: 1,166 Days
• Field of Search: 709/234, 370/231
• US Class Current: 709/234
• CPC Class Codes: H04L 47/10 Flow control; Congestion control
• CPC Class Codes: H04L 47/20 Traffic policing
• CPC Class Codes: H04L 47/2408 for supporting different services, e.g. a differentiated services [DiffServ] type of service
• CPC Class Codes: H04L 47/2458 Modification of priorities while in transit
• CPC Class Codes: H04L 47/266 Stopping or restarting the source, e.g. X-on or X-off
• CPC Class Codes: H04L 47/30 in combination with information about buffer occupancy at either end or at transit nodes
• CPC Class Codes: H04L 47/431 using padding or de-padding
• CPC Class Codes: Y02D 30/50 in wire-line communication networks, e.g. low power modes or reduced link rate

Abstract

Method and apparatus are disclosed for flow control over Point-to-Point Protocol (PPP) data links. A method of negotiating such flow control between two PPP peers is disclosed, along with methods for operating flow control across a PPP link. In one embodiment, flow control frames carry an IEEE802.3x MAC control frame payload—the PPP implementation repackages such frames as MAC control frames and passes them to a MAC, which performs flow control. In another embodiment, flow control frames allow flow control commands to be applied differently to different service classes such that PPP flow can be controlled on a per-class basis.

Claims

1. A method of operating a packet-processing device comprising:

receiving a point-to-point protocol packet stream from a point-to-point protocol peer over a point-to-point protocol full-duplex data link;

scanning the protocol type field of packets in the stream for a frame having a point-to-point flow control protocol type; and

when a point-to-point flow control frame is detected in the packet stream, decoding the contents of that frame, and adjusting the flow rate of an ongoing outbound packet stream on the data link according to at least one flow control instruction contained in that flow control frame.

2. The method of claim 1, wherein multiple point-to-point flow control frame protocol types can exist in the packet stream, and wherein the decoding and adjusting methods differ depending on the flow control frame protocol type.

3. The method of claim 1, wherein decoding the contents of a flow control frame comprises repackaging that frame as a flow control frame of another protocol recognizable by a downstream processor within the device.

4. The method of claim 3, wherein adjusting the flow rate comprises recognizing the repackaged flow control frame at the downstream processor and adjusting the flow rate of the outgoing packet stream prior to point-to-point protocol processing.

5. The method of claim 3, wherein the another protocol is IEEE802.3x and the downstream processor functions as an IEEE802o3 media access controller.

6. The method of claim 1, wherein decoding the contents of a flow control frame comprises:

depackaging flow control instructions identified by a service identifier;

communicating the depackaged flow control instructions to a packet scheduler; and

adjusting the flow rate of packets corresponding to the service identifier and destined for the outgoing data stream, according to the flow control instructions.